is this for yer 66? check the spline count on the trans [coarse on the old one, fine on the Sag] and the various shaft yokes, if the right length doesn't have the right spline yoke, they're not hard to switch
"When we tug a single thing in nature, we find it attached to the rest of the world" ~ John Muir "When we tug a single thing on an old truck, we find it falls off" ~ me Some TF series details & TF heater pics